Effect of two different haptics to centering of intraocular lens

1
Effect of two different haptics to centering of
intraocular lens
Mayumi Nagata1,2, Hiroyuki Matsushima1, Wataru
Terauchi1 and Tadashi Senoo1 1Department of
Ophthalmology, Dokkyo Medical University,
Tochigi, JAPAN 2Saiseikai Utsunomiya Hospital,
Tochigi, JAPAN
The authors have no financial interest in the
subject matter of this poster.
2
PURPOSE

• Tilt and decentration of intraocular lens (IOL)
  influent visual function for resent IOLs. And
  complete continuous curvilinear capsulorhexis
  (CCC) is important to prevent tilt and
  decentration.
• In this study, we concentrate the relationship
  between shapes of haptics and intracapsular
  stability of the IOL.

Eppig T. Effect of decentration and tilt on the
image quality of aspheric intraocular lens
designs in a model eye. J Cataract Refract Surg.
2009351091-1100
3
MATERIALS and PATIENTS
Wide Haptics Thin Haptics

Types of IOL SN60WF, Alcon FY-60AD, HOYA
Optics Acrylic Acrylic
Haptics Acrylic PMMA
Characteristics of Haptics Soft and low repulsion Hard and high repulsion
Patients 74 eyes 52 eyes
4
Question 1 Do the shape of CCC and IOL Haptic
influence on IOL decentration?
Analysis 1 Measurement of IOL decentration
CC (complete cover) group NCC (non complete cover) group

1. Images were taken using an EAS-1000 (NIDEK),
and patients were divided into the CCC was
covered the IOL optic (CC group), and the part of
the CCC was outside the IOL optic (NCC group).
2. At 3 months after surgery, the decentration
of IOLs were analyzed. The IOL decentration of 2
groups (CC group and NCC group) were compared in
2 different types of IOLs. (Unpaired-t test are
used for statistical analysis.)
5
Results 1 Measurement of IOL decentration
Wide Haptics
Thin Haptics
CC group NCC group CC group NCC group

0.170.07mm 0.320.27mm 0.150.09 mm 0.250.08 mm
(n44)
(n33)
(n30)
(n22)


Statistically significance (Plt0.05)
Answer 1 Decentration was significantly larger
in the NCC group than in the CC
group. Decentration of Wide Haptics was larger
than Thin Haptics in NCC group.
6
Question 2 Why do IOLs decentrate in the NCC
group? Why decentration of Wide Haptics was
large?
Analysis 2 Relationships between direction of
IOL decentration and area of NCC

• 1. Direction of IOL Decentration (DID)
• Center of pupil A and center of IOL B are
  decided. Direction from A to B is defined as
  direction of IOL decentration.
• 2. Direction of NCC Area (DNCC)
• Center of NCC area C is decided. Direction
  from A to C is defined as direction of NCC.
• 3. Correlation between direction of IOL
  decentration and direction of NCC were
  analyzed (Pearsons correlation coefficient).

C
7
Results 2 Relationships between direction of IOL
decentration and area of NCC
Wide Haptics
Thin Haptics
DID(Degree)
DID(Degree)
DNCC180(Degree)
DNCC180(Degree)
Correlation coefficient0.365
Correlation coefficient0.599
Answer 2 The IOLs move to opposite direction
from the NCC area in the Wide Haptics however,
there are no correlation in the Thin Haptics.
8
Why the IOLs move to opposite direction from the
NCC area? Why the Wide Haptics decentrate
easily?
Wide Haptics
Soft haptics are not enough to prevent the IOL
dislocation.
Thin Haptics
Hard haptics prevent the IOL dislocation.


Strong adhesion of NCC dislocate IOL toward
opposite direction from the NCC area.
9
Question 3 How to prevent decentration of IOL
in case of NCC?
Analysis 3 Relationships between IOL
decentration and position of IOL haptics

• The NCC group was divided into a group which the
  haptic was fixed to the NCC region (Haptic on NCC
  group), and a group which the haptic was fixed to
  the CC region (Haptic on CC group).
• 2. Comparison the IOL decentration (the data of 3
  months after surgery) of 2 groups were performed.

Haptic on CC group
Haptic on NCC group
Position of Haptics
Area of NCC
10
Results 1 Measurement of IOL decentration
Wide Haptics
Thin Haptics
Haptic on CC Haptic on NCC Haptic on CC Haptic on NCC

0.290.08mm 0.220.08mm 0.270.09 mm 0.230.06 mm
(n20)
(n13)
(n9)
(n13)

Statistically significance (Plt0.05)
Answer 3 In Wide Haptics, the placement of
wide haptics to NCC area prevent the IOL
decentration.
11
Why does the placement of haptics on NCC area
prevent the IOL decentration only in the Wide
Haptics?
Wide Haptics
Thin Haptics
The wide haptic inhibit adhesion between anterior
and posterior capsules. Then the movement of IOL
is prevented.
The thin haptic is not enough to inhibit adhesion
between anterior and posterior capsules. Then
the placement of haptics is not effective to
prevent the IOL decentration.
12
CONCLUSIONS

• The IOL decentration was significantly larger in
  the NCC group than in the CC group.
• The IOLs move to opposite direction from the NCC
  area in the Wide Haptics however, there are no
  correlation in the Thin Haptics.
• In Wide Haptics, the placement of wide haptics
  to NCC area prevent the IOL decentration.